"I URGE YOU TO STOP"
The Russian defence ministry denied Prigozhin's claims of an attack on his forces, saying the statements "do not correspond to reality", and calling them a "provocation".
It later said Ukrainian troops were taking advantage of the infighting to ready an assault near the east Ukraine hotspot of Bakhmut.
A prominent Russian general urged Prigozhin to call off efforts to remove the leadership of Moscow's defence ministry.
"I urge you to stop," Sergei Surovikin, commander of Russia's aerospace forces, said in a highly unusual video address.
"The enemy is just waiting for the internal political situation to worsen in our country. Before it is too late, it is necessary ... to obey the will and order of the popularly elected President of the Russian Federation".
Anti-Kremlin figure Mikhail Khodorkovsky, however, urged Russians to support Prigozhin, saying it was acceptable to back "even the devil" in taking on the Kremlin.
Washington-based think tank the Institute for the Study of War said the Wagner chief's attempt to force a leadership change in the defence ministry "is unlikely to succeed" given that Surovikin had denounced his call for rebellion.
Kyiv's defence ministry said it was monitoring the situation.
"We are watching," the Ukrainian defence ministry tweeted, while Ukraine's military intelligence chief Kyrylo Budanov said rival Russian factions had begun to "eat each other over power and money".
Ukraine was also on high alert after new Russian missile strikes Saturday, with explosions reported in Kyiv and the eastern city of Kharkiv.
US President Joe Biden had been briefed on the situation in Russia and Washington "will be consulting with allies and partners on these developments", National Security Council spokesman Adam Hodge said.
On Friday, Prigozhin said Moscow's forces were retreating in Ukraine's east and south following the start of Kyiv's counteroffensive early this month. That directly contradicted Putin's account that Ukraine was suffering "catastrophic" losses and that there was a lull in fighting.
"We are washing ourselves in blood," Prigozhin said.
"No one is bringing reserves. What they tell us is the deepest deception," he added, referring to the Russian military and political leadership.
QUESTIONING MILITARY OPERATION
After years of operating in the shadows, Prigozhin has now admitted to running the elusive mercenary group Wagner and even interfering in US elections.
His forces, bolstered by tens of thousands of prison recruits, played a central role in Russia's capture of the town of Bakhmut in the eastern region of Donetsk, the longest and bloodiest battle of the conflict.
However, this week he accused Moscow's top brass of deceiving Russians about the offensive in Ukraine.
"Why did the special military operation begin?" he said. "The war was needed for the self-promotion of a bunch of bastards."
Rarely has such a controversial figure shot to this degree of prominence on the Russian political stage under Putin.
Prigozhin rose from a modest background to become part of the inner circle around Putin.
He spent nine years in prison in the final period of the USSR after being convicted of fraud and theft. In the chaos of the 1990s, he began a moderately successful business selling hot dogs.
From there he fell into the restaurant business and opened a luxury location in Saint Petersburg whose customers included Putin, then making the transition from working in the KGB to local politics.
However, in recent months, Prigozhin has become embroiled in a bitter power struggle with the defence ministry.
He has accused the Russian military of attempting to "steal" victories in Ukraine from his forces, and slammed Moscow's "monstrous bureaucracy" for slowing military gains.
